Results of recent Free Electron Laser (FEL) studies have shown that under certain conditions pulsed 6-7 5m radiation can affect scission of soft tissues with unprecedented precision and minimal damage to tissues immediately adjacent to the scission sites. Subsequent clinical work has successfully employed this FEL output in several pilot human neurosurgeries. Until recently, only facility-sized FELs had been able to produce the required light pulse characteristics, but such facilities are incompatible with general clinical use. Light Age, Inc. has developed and built a table-top, solid state-based laser source, having the output characteristics of the FEL. In Phase I, this laser was installed at Vanderbilt University, where comparative tissue studies have been conducted. These studies have confirmed the substantial equivalence between the new laser source and the FEL, with respect to in-vitro tissue ablation. These results indicate that this new laser source should be suitable for wider clinical use in a variety of surgical procedures for which the FEL has been demonstrated to be effective. The new laser system is based upon a robust tunable solid-state laser source (alexandrite) and a two-stage Raman conversion process. The alexandrite pump laser technology is already employed in routine medical application throughout the world;and the Raman convertor technology has been employed in a variety of scientific laser systems. In this proposed Phase II effort, in conjunction with collaborators at Vanderbilt, further work will be conducted to develop and demonstrate a compact medical device suitable for routine neurosurgical application. Our Phase II work features advanced laser development and surgical demonstrations on live pigs. Because the approvals and facilities for human studies are already in place, this technology can move quickly into clinical trials in later follow-on studies. The ability of this laser technology to be integrated into a compact and reliable computer-controlled system provides an exciting opportunity to extend the fruits of the FEL research into general clinical practice, with promising near and long-term benefits for neural, retinal, and other precision surgeries. The importance of this work has been heightened due to the recent federal funding reduction that has led to the shut down of the FEL operation at the Keck facility. Now, the only way clinical development of the surgical procedures can proceed is through the work proposed here. PUBLIC HEALTH RELEVANCE: The purpose of this program is to develop a clinical laser that serves as a routine tool for surgeries, especially in the optic nerve, brain, and spine, where extreme precision is needed and where inadvertent damage to adjacent tissue is unacceptable. The resulting surgical tool will be compact and relatively inexpensive, and thus suitable for use by clinics around the world. The advanced surgical procedures that would result can be readily introduced into most hospitals and specialty clinics at reasonable cost and for general human benefit.